Full-color emissive organosilicon-coated carbon dots microspheres for latent fingerprint development with level 3 details

Organosilicon-coated carbon dots (OSiCDs) microspheres were synthesized by one-step solvothermal method in which phenylenediamine-derived CDs were encapsulated by organosilicon network structure to achieve blue, yellow and red emissive solid-state fluorescent powder. The influence of the three isomers of phenylenediamine on the solid-state fluorescence of OSiCDs microspheres were characterized in detail. Furthermore, the fluorescence stability of three kinds of OSiCDs microspheres were measured and exhibited excellent stability, which facilitate the acquisition and preservation of fingerprint patterns. The OSiCDs microspheres used as a fluorescence developer were further applied to capture the latent fingerprints (LFPs) on different substrate surfaces. The results indicate that the OSiCDs microspheres can efficiently eliminate background interferences of challenging surfaces, such as multicolored or patterned substrates, and the identified LFPs have clear patterns with high-resolution fluorescence, enabling fluorescent fingerprint recognition at three levels (core, hole, island, and fork). The as-prepared OSiCDs microspheres show great promise in practical application scenarios for fingerprint development.